Synthetic thread and method of producing the same



Nov. 10, 1959 N.F. VANDERVOORT SYNTHETIC THREAD AND METHOD OF PRODUCINGTHE SAME led Feb. 5, 1957 i H w cw,

lllulll IN VEN TOR. #0191714 B l/swpfm/aaw' United States PatentOSYNTHETIC THREAD METHOD OF PRODUCING THE SAME Norman F. Vandervoort,Ridgewood, N.J., assignor to The Mason Silk Company, Winsted, Conn., acorporationof Connecticut Application February 5, 1957, Serial No.638,315

4 Claims. (Cl. 57-140) 7 leave runs or allow seams to open: The presentinvention, therefore, has for an object to produce a synthetic orartificial thermoplastic thread which will form a seam that will not runback or slip when employed as a sewing thread.

Another object of the invention is to provide a synthetic thermoplasticthread having a fibrous surface whereby a relatively rougher surface andincreased bulk is imparted thereto. The increased roughness and bulkprevents relative slippage of the thread and the thread more closelyfits the eye of the usual sewing machine needle. Furthermore, when usedfor sewing the increased roughness and bulkiness reduces the temperatureof the sewing machine needle which has been one of the problemsencountered in the use of conventional synthetic thermoplastic thread.

Another object of the invention is to provide a synthetic or artificialthermoplastic thread which has advantages for use as a sewing machinethread.

Another object of the invention is to provide a synthetic or artificialthermoplastic thread which has advantages over the conventional type ofthermoplastic thread for tailoring purposes whereby the improved threadis less conspicuous and color matching may be improved due to theroughness of the surface.

The invention also relates to a method of producing a synthetic orartificial thermoplastic thread of the aforesaid character.

In carrying out the process a plurality of artificial thermoplasticfilaments are twisted to impart any desired number of turns thereto andthe resulting strand is then treated to distort the filaments to producea flufiing out thereof from the surface of the strand in the form ofloops with a resulting increase in bulkiness of the strand and areduction in length thereof. This may be carried out as shown in thedrawings in which:

Fig. 1 is a sectional view of an air nozzle through which the twistedstrand is passed for producing the looping fibrous characteristics tothe surface thereof.

Fig. 2 is a view of the completed thread.

Fig. 3 is a sectional view taken approximately on line 33 of Fig. l.

The air nozzle illustrated in the drawings is formed with an air inlet11, an air outlet 12 and a passageway 13 therebetween. A needle 14having an opening 15 therethrough extends into the nozzle with the innerend 21 thereof opening into a venturi 16 of a tubular member 17 securedin the outlet end of the passageway 13. The

2,911,784 Patented Nov. 10, 19 59 needle 14 is mounted in a plug 18secured in an opening 19 in the nozzle.

A strand composed of a plurality of thermoplastic filaments is drawnthrough the needle 14 and then through the venturi 16 and out throughthe outlet end 12. The venturi 16 constricts the air passageway so as tomaterially increase the velocity of the air at the location where thestrand enters the venturi. This produces a fluflfing out of thefilaments of the strand in the form of loops 20 as well as an increasein bulkiness and reduction in the length of the strand. The increasedbulkiness in the strand may vary from 2 to 30 percent and the reductionin the length of the strand may also vary from 2 to 30 percent. Thepressure of the air at the inlet of the nozzle may be 45 pounds persquare inch and the strand may be drawn through the nozzle at a rate ofyards per minute for certain types of thermoplastic filaments.

The thread is produced in accordance with the following steps:

A plurality of continuous thermoplastic filaments are twisted to impartany desired number of turns ranging from two turns per inch to twentyfive turns per inch and preferably twelve to fourteen turns per inch.

The strand is then treated to distort the filaments to produce afluffing out thereof from the surface of the strand in the form of loopswith a resultingincrease in bulkiness of the strand and a reduction inlength thereof.

The twisted and treated strand is again twisted in the same direction asin the direction of the original twist imparted thereto. Eight to thirtyadditional turns per inch may be imparted thereto varying with the typeand size of the thread to be produced. On coarse strands no additionaltwist may be required.

Several of the twisted and treated strands are then twisted together,the direction of twisting being opposite to that imparted to theindividual strands. The number of strands twisted together may consistof two to ten and the turns per inch imparted thereto are usuallysomewhat less in number than the total number of turns imparted to thefilaments in producing the strands.

The twisted strands are then stabilized by setting with heat or steam orother suitable means to complete the formation of the thread S.

Instead of stabilizing the strands by heat or steam, each strand may bestabilized by coating the same with an adhesive applied thereto afterthe strand has been treated to form the loops 20 in the filaments. Theadhesive may consist of six parts nylon resin dissolved in eightyfourparts ethyl alcohol and ten parts of water after which the adhesive isdried. The resulting adhesive coating consists of approximately 5% ofthe weight of the finished thread.

The following are examples of the thread produced in accordance with theinvention:

Example 1 Using 70 denier composed of 34 nylon filaments, twist 12 righthand turns per inch to form a strand.

Treat the strand to impart the loops20 to the filaments thereof with areduction of 10 percent in length.

Twist the treated strand to impart 11 right hand turns per inch.

Twist three of the treated and twisted strands together to impart 17left hand turns per inch to form the thread.

Stabilize the thread by heat or steam or stabilize each strand bycoating the same with an adhesive after the same has been treated toform the loops 20 in the filaments.

Example 2 Using 100 denier composed of 34 nylon filaments, twist 12 lefthand turns per inch to form a strand.

Example 3 Using 210 denier composed of 34 nylon filaments, twist .12right hand turns per inch to form a strand.

Treat the strand to impart the loops 20 to the filaments thereof with areduction of 10% in length.

Twist four of the treated and twisted strands together to impart 10 lefthand turns per inch to form the thread. Stabilize the thread by heat orsteam or stabilize each strand by coating the same with an adhesiveafter the same has been treated to form the loops 20 in the filaments.

Example 4 Using a bundle of any desired number of thermoplasticfilaments, form a strand of any desired denier.

Treat the strand to impart the loops 20 to the filaments thereof withany desired reduction in length.

Twist any desired number of the treated strands together to impart anydesired number of turns thereto per inch to form a thread.

Stabilize the thread in any desired manner.

Example 5 Using 70 denier composed of 34 nylon filaments, treat toimpart loops 20 to the filaments thereof with a reduction of 5% inlength.

Twist the treated filaments 22 right hand turns per inch to fonn astrand.

Twist 2 of the treated and twisted strands together to i impart 17 lefthand turns per inch to form the thread.

Stabilize the thread by heat or steam or stabilize each strand bycoating the same with an adhesive after the same has been treated toform the loops 20 in the filaments and twisted.

-What is claimed is:

1. A method of producing a thermoplastic sewing thread comprisingtwisting a plurality of thermoplastic filaments together in onedirection a plurality of times per inch of length to provide a strand oftwisted filaments, treating the strand to form outwardly projectingloops in the filaments thereof, twisting the treated strand not lessthan eight nor more than thirty additional turns per inch of length inthe same direction as the original twist, twisting a plurality of saidtreated and twisted strands together a plurality of times per inch oflength in a direction opposite to the aforesaid twisting to thereby forma thread, and treating the thread to stabilize the same.

2. A method of producing a thermoplastic sewing thread comprisingtwisting a plurality of thermoplastic filaments together in onedirection a plurality of times per inch of length to provide a strand oftwisted filaments, treating the strand to shorten the same and to formoutwardly projecting loops in the filaments thereof, twisting thetreated strands not less than eight nor more than thirty additionalturns per inch of length in the same direction as the original twist,twisting a plurality of said treated and twisted strands together aplurality of times per inch of length in a direction opposite to theaforesaid twisting to thereby form a thread, and treating the thread tostabilize the same.

3. A method of producing a thermoplastic sewing thread comprisingtwisting a plurality of thermoplastic filaments together in onedirection a plurality of times per inch of length to provide a strand oftwisted filaments, treating the strand to shorten and increase thebulkiness of the same and to form outwardly projecting loops in thefilaments thereof, twisting the treated strand not less than eight normore than thirty additional turns per inch of length in the samedirection as the original twist, twisting a plurality of said treatedand twisted strands together a plurality of times per inch of length ina directiorropposite to the aforesaid twisting to thereby form a thread,and treating the thread to stabilize the same.

4. A thermoplastic sewing thread composed of a plurality of strandstwisted together a plurality of times in a uniform direction, each ofsaid strands being composed of a plurality of thermoplastic filamentshaving outwardly projecting loops arranged at random intervals along thefilaments, and the thermoplastic filaments of each of said strands beingtwisted together not less than eight nor more than thirty turns per inchof length in a direction opposite to the aforesaid twisting of thestrands whereby the aforesaid loops of the filaments are arranged withinand on the surface of the body of each strand.

References Cited in the file of this patent UNITED STATES PATENTS

